Lawn mowing equipment using a single blade rotated in a plane parallel to the ground has largely replaced reel type lawn mowers. The blade of a rotary mower is rotated at high speeds, severing individual blades of grass as the blade passes through the grass. The currents of air generated by the rotating blade generally cause the blades of grass to be lifted upright as the rotary lawn mower advances over the ground, thereby contributing to an even cut.
The cutting edge of a rotary lawn mower blade is subject to extreme operating conditions. The blade is rotated at high speeds, and can frequently come into contact with sticks, rocks, and other debris located on the ground. Maintaining the cutting edge of a rotary mower blade in a sharpened condition is important to the evenness and cleanness of the cut. In particular, a dull blade tends to tear, rather than sever, individual blades of grass, detracting from the overall health of the individual blades of grass, and from the overall appearance of the lawn.
Heretofore, maintaining the blade of a rotary lawn mower has entailed the time-consuming, and often difficult, job of completely removing the blade from the mower. A rotary blade having a cutting edge that could be replaced without complete removal of the blade from a lawn mowing machine would provide a decided advantage.